Conversion disorder
Conversion disorder was a formerly diagnosed psychiatric disorder characterized by abnormal sensory experiences and movement problems during periods of high psychological stress. Individuals diagnosed with CD presented with highly distressing neurological symptoms such as numbness, blindness, paralysis, or convulsions, none of which were consistent with a well-established organic cause and could be traced back to a psychological trigger. CD is no longer a diagnosis in the WHO's ICD-11 or APA's DSM-5 and was superseded by functional neurologic disorder, a similar diagnosis that notably removed the requirement for a psychological stressor to be present.
It was thought that these symptoms arise in response to stressful situations affecting a patient's mental health. Individuals diagnosed with conversion disorder have a greater chance of experiencing certain psychiatric disorders including anxiety disorders, mood disorders, and personality disorders compared to those diagnosed with neurological disorders.
Conversion disorder was partly retained in the DSM-5-TR and ICD-11, but was renamed to functional neurological symptom disorder and dissociative neurological symptom disorder, respectively. FNSD covers a similar range of symptoms found in conversion disorder, but does not include the requirements for a psychological stressor to be present. The new criteria no longer require feigning to be disproven before diagnosing FNSD. A fifth criterion describing a limitation in sexual functioning that was included in the DSM-IV was removed in the DSM-5 as well. The ICD-11 classifies DNSD as a dissociative disorder with unspecified neurological symptoms.
Signs and symptoms
Conversion disorder presented with symptoms following exposure to a certain stressor, typically associated with trauma or psychological distress. Usually, the physical symptoms of the disorder affect the senses or movement. Common symptoms included blindness, partial or total paralysis, inability to speak, deafness, numbness, difficulty swallowing, incontinence, balance problems, non-epileptic seizures, tremors, and difficulty walking. Feelings of breathlessness were said to have possibly indicated conversion disorder or sleep paralysis.Sleep paralysis and narcolepsy can be ruled out with sleep tests. These symptoms were attributed to conversion disorder when a medical explanation for the conditions cannot be found. Symptoms of conversion disorder usually occur suddenly. Conversion disorder was typically observed in people ages 10 to 35, affecting between 0.011% and 0.5% of the general population.
Conversion disorder presented motor or sensory symptoms including:
Motor symptoms or deficits:
- Impaired coordination or balance
- Weakness/paralysis of a limb or the entire body
- Impairment or loss of speech
- Difficulty swallowing or a sensation of a lump in the throat
- Urinary retention
- Psychogenic non-epileptic seizures or convulsions
- Persistent dystonia
- Tremor, myoclonus or other movement disorders
- Gait problems
- Loss of consciousness
- Impaired vision, double vision
- Impaired hearing
- Loss or disturbance of touch or pain sensation
Sexual dysfunction and pain were also considered symptoms of conversion disorder, but if a patient only has these symptoms, they should be diagnosed with sexual pain disorder or pain disorder.
Diagnosis
Definition
Conversion disorder is now partly contained under functional neurological symptom disorder. In cases of conversion disorder, there is a psychological stressor.The diagnostic criteria for functional neurologic symptom disorder, as set out in DSM-5, are:
Specify type of symptom or deficit as:
- With weakness or paralysis
- With abnormal movement
- With swallowing symptoms
- With speech symptoms
- With attacks or seizures
- With amnesia or memory loss
- With special sensory loss symptoms
- With mixed symptoms.
- Acute episode: symptoms present for less than six months
- Persistent: symptoms present for six months or more.
- Psychological stressor
- No psychological stressor
Exclusion of neurological disease
In excluding neurological disease, the neurologist has traditionally relied partly on the presence of positive signs of conversion disorder. The validity of many of these signs has been questioned by a study showing that they also occur in neurological disease. One such symptom, for example, is la belle indifférence, described in DSM-IV as "a relative lack of concern about the nature or implications of the symptoms". In a 2006 study, no evidence was found that patients with functional symptoms are any more likely to exhibit this than patients with a confirmed organic disease. In the DSM-5, la belle indifférence was removed as a diagnostic criterion.
Another feature thought to be important was that symptoms tended to be more severe on the non-dominant, usually left side of the body. There have been a number of theories about this, such as the relative involvement of cerebral hemispheres in emotional processing, or more simply, that it was "easier" to live with a functional deficit on the non-dominant side. However, a literature review of 121 studies established that this was not true, with publication bias the most likely explanation for this commonly held view. Although agitation is often assumed to be a positive sign of conversion disorder, release of epinephrine is a well-demonstrated cause of paralysis from hypokalemic periodic paralysis.
Misdiagnosis does sometimes occur. In a highly influential study from the 1960s, Eliot Slater demonstrated that misdiagnoses had occurred in one third of his 112 patients with conversion disorder. Later authors have argued that the paper was flawed. A 2005 meta-analysis has shown that misdiagnosis rates since that paper was published are around four percent, the same as for other neurological diseases.
Psychological mechanism
The psychological mechanism of conversion can be the most difficult aspect of a conversion disorder diagnosis. Even if there is a clear antecedent trauma or other possible psychological trigger, it is still not clear exactly how this gives rise to the symptoms observed. Patients with medically unexplained neurological symptoms may not have any psychological stressor, hence the use of the term "functional neurological symptom disorder" in the DSM-5, as opposed to "conversion disorder", and the DSM-5's removal of the need for a psychological trigger. The change of name in the DSM-5 also came with a change of criteria. There was a removal of connection to sexual functioning as well as relation to any other medical condition. There was also an added connection to social and occupational functioning.Treatment
Treatments for conversion disorder included hypnosis, psychotherapy, physical therapy, and stress management. Treatment plans will consider duration and presentation of symptoms and may include one or multiple of the above treatments. This may include the following:- Occupational therapy to maintain autonomy in activities of daily living.
- Treatment of comorbid depression or anxiety if present.
- Educating patients on the causes of their symptoms might help them learn to manage both the psychiatric and physical aspects of their condition. Psychological counseling is often warranted given the known relationship between conversion disorder and emotional trauma. This approach ideally takes place alongside other types of treatment.
- Medications such as serotonin–norepinephrine reuptake inhibitors, a class of antidepressants, and sedatives such as benzodiazepines may help reduce stress and also relieve or prevent symptoms from occurring.